Hydrophobic Surface Induced Biosorption and Microbial Ex Situ Remediation of Oil-Contaminated Sites

Microbial bioremediation of spilled oil is the most sustainable and eco-friendly approach, yet the slower biodegradation rate remains a challenge for researchers. An integrated strategy of biodegradation along with a faster removal method like adsorption is one of the options available to address this challenge. In this study, we have explored the surface-induced biosorption coupled microbial biodegradation approach for effective remediation. Low-cost bagasse was used as a biosorbent and its surface hydrophobicity was improved by forming octyl self-assembled monolayers to enhance the surface-oil interactions (adsorption). Pseudomonas aeruginosa was exploited for biodegradation because of its known oil degradation and biosurfactant production abilities. An enhanced oil adsorption capacity of 6.9 ± 0.3 g/g was obtained after surface modification of the bagasse. The rate of adsorption was 2.5 fold higher as compared to unmodified bagasse. A kinetic model is proposed for the integrated process, which agreed to simultaneous biosorption and biodegradation. The microbial oil biodegradation rate was improved by 17 fold in the case of the integrated process. This integrated approach was found to synergistically improve the overall remediation of crude oil, which was also correlated with alkane hydroxylase activity and biosurfactant production. Preadsorbed oil on hydrophobic bagasse improved oil availability for the adhered microbes. Further, the synthesis of biosurfactant amended the biodegradation process. Hence, in the foreseeable future, hydrophobic biosorbents with excellent adsorption capacity, stability, and reusability shall be potential carriers for the bioremediation of contaminated sites.